Brake control mechanism



p 1937- c. QFARMER BRAKE CONTROL MECHANISM Filed Jan. 10, 1936 INVENTOR CLYDE EZ. |='AF\'MEF\ ATTORNEY Patented Sept. 7, 1937 UNITED STATES PATENT OFFICE BRAKE CONTROL MECHANISM Clyde 0. Farmer, Pittsburgh, Pa., assignor to The Westinghouse Air Brake Company, Wilmerding, Pa., a corporation of Pennsylvania Application January 10, 1936, Serial No. 58,487

This invention relates to brake equipment for 6 Claims.

vehicles and more particularly to brake con-' trolling means for automatically controlling the degree of application of the brakes.

It has heretofore been proposed to provide brake equipment for vehicles designed for modcm high speed able controller service having a manually operfor governing the operation of brake control mechanism to cause an application of the brakes to a degree dependent upon the amount of movement of the manually operable device from its release position, and to provide a retardation controller device responsive to the rate of retarda tion of the vehicle for also governing the operation of the brake control mechanism to limit the degree of application of the brakes independently of the position of the manually operable retardation of the vehicle to a desir-edvalue.

controller to limit the rate of In such a brake system the control of the brakes is taken from the operator by the retardation conthe operator.

It is an object of my invention to provide, in a brake equipment of the above indicated character, means responsive to a retardation controller device for cont rolling the degree of application of the brakes through operation of the manually operable controller.

It is another object of my invention to provide a brake equipment of the above indicated character in which the operator will be aware of the retardation controller becoming effective to control the brakes, sires, resist the and in which he may, if he detaking over of the control of the brakes by the retardation controller.

Other objects and advantages of my invention will be apparent from the following description of one preferred embodiment thereof when read withreference to the accompanying drawing, in which the single figure is a diagrammatic view, partly in section, of a brake system embodying my invention.

As shown in the drawing, the brake system may include a fluid pressure brake equipment comprising a self-lapping brake Valve device I, a brake cylinder 2, and a main reservoir 3, a magnetic track brake comprising a track shoe 4 adapted to engage the rail 5, and dynamic braking equipment comprising a vehicle driving motor 6 adapted to operate as an electric generator for, supplying current to a dynamic braking resistor l. A manually operable braking controller 8 is provided for controlling the operation of the brake system, and a retardation controller 9 and a magnet valve device it are provided for regulating the degree of application of the brakes to limit the rate of retardation of the vehicle toa predetermined value.

The self-lapping brake valve device I may be of any suitable type, and for the purpose of illustration is shown in outline form as similar to the type disclosed in the United States Patent No. 2,012,747 of John W. Logan, Jr. (see Figs. 1 and 2). The brake valve device I is provided with an operating lever l2 attached to a rotatable shaft [3, said lever being connected at its upper end to a spring l4 and at its lower end to a cable Hi. When the lever I2 is turned in a clockwise direction the brake valve device is operative tosupply fluid under pressure from the main reservoir 3 through a pipe Ill and a pipe l8 to the brake cylinder 2, and when the spring I4 is permitted to move said lever in the opposite direction said device is operative to release fluid under pressure from the brake cylinder.

The braking controller 8 comprises a casing containing a rotatable drum 2!, which drum is secured to an axially disposed shaft 22 suitably journaled in the casing. The drum 26 is adapted to be manually operated by means of a handle 23 secured to the upper end of the shaft 22.

Conducting segments 25, 26, 21 and 28 are mounted on the drum 2|. The conducting segments 25 and 26 are adapted to control the supply of power to the driving motor 6, the conducting segment 21 is adapted to control the supply of current to the winding of the track shoe 4, and the conducting segment 28 is adapted to control operation of the motor 6 as a dynamic brake. Secured to the shaft 22 below the drum 2| is a member 29, to which is attached the end of the cable I5 for operating the brake valve device, said member 29 being adapted to pull the cable to the left when the braking controller 8 is moved toward an application position.

Contained in a cylinder portion 3! of the braking controller casing is a piston 32 which has at one side a piston chamber 33. The piston carries a stem 34 provided with a rack 35 having teeth adapted to mesh with the teeth of a pinion 38, which pinion is secured to the lower end of the rotatable shaft 22 of the braking controller 8.

The magnet valve device I!) comprises a casing containing a supply valve 38 and a vent valve 4|, said supply valve 38 being disposed in a valve chamber 39 connected through a choke fitting having a restricted passage 40 to the main reservoir pipe I1, and said vent valve 4| being disposed in a chamber 42 open to the atmosphere through a passage 43. The valves 38 and 4| are connected together by a fluted stem 44 and are adapted to control the supply and release of fluid under pressure through a bore 45 in which said stem is guided, which bore is open through a pipe 41 to the chamber 33 in the braking controller 8. A stem 58 is provided on the vent valve 4|, and is secured to an armature adapted to be actuated by a magnet 5| when energized for seating the valve 4| and unseating the valve 38, the movement of the valves being opposed by a spring 49 contained in the chamber 39, which spring acts against the supply valve 38 for normally maintaining said valve 38 seated and vent valve 4| unseated.

The retardation controller 9 may be of any suitable type, and as shown in diagrammatic form in the drawing comprises a pendulum 53, which is pivotally supported by a pin 54 secured to a support member 55, and which carries a contact plate 55, suitable insulating means being interposed between said plate and the pendulum. The pendulum 53 is so mounted on the vehicle as to be swung to the left in accordance with the inertia effect set up during deceleration of the vehicle when the brakes are applied, the contact plate 56 being adapted to bridge a pair of stationary contacts 51 when the rate of retardation of the vehicle exceeds a given rate.

In operation, with the braking controller 8 in the release position, as shown in the drawing, the contact segment 25 on the drum 2| bridges contact fingers 58 and 59, while the contact segment 25 bridges contact fingers and 6|, thus bridging a link in a circuit that is controlled by the controller 55 for supplying current to the driving motor 6, the circuit being from the overhead conductor 63, through trolley 64, conductor 65, motormans controller 65, conductor 51, contact finger 58, contact segment 25, contact finger 59, conductor 68, the field and armature windings 69 and 18 of the motor, conductor contact finger 6|], contact segment 26, contact finger BI and grounded conductor 12.

If it is desired to apply the brakes, the braking controller 8 is moved out of the release position through the medium of the handle 23, the initial movement serving to disengage the contact segments 25 and 26 from the contact fingers 53, 59, 68 and 6|, thereby interrupting the circuit through which current is normally supplied to the motor 8. As the braking controller is moved into the application zone to a degree according to the desired degree of braking, the member 29 is turned so as to pull the cable l5 to the left, turning the lever |2 of the self-lapping brake valve device I in a clockwise direction for supplying fluid under pressure from the main reservoir 3 to the brake cylinder 2 to effect an initial application of the fluid pressure brake.

At substantially the same time, the contact segment 28 on the drum 2| is moved so as to connect the contact finger 59 with a contact finger 13,

thus completing a dynamic braking circuit from one terminal of the armature winding 10, through the field winding 69, conductor 68, contact finger 59, contact segment 28, contact finger 13 and the dynamic braking resistor to the other terminal of the armature winding.

As the braking controller 8 is thus moved into the application zone, the contact segment 21 bridges two contact fingers I5 and 18. A circuit is then completed for energizing the windings of the track shoe 4, the energizing circuit being from the overhead conductor 63, to the trolley 64, through the conductor 65, the connected contact fingers I5 and 16, a resistance element 11, a conductor I8, the track shoe 4 and grounded conductor 19. The resistance element 11 is provided with contact fingers 8a] which are adapted to be successively engaged by the contact segment 21, upon further movement of the drum 2| into the application zone, for gradually shunting out the resistance 11 and increasing the current supplied to the track shoe.

As the application of the brakes initiated as just described becomes effective, the pendulum 53 of the retardation controller 9 is urged to the left due to the force of inertia set up upon deceleration of the vehicle. If the amount of movement of the controller handle 23 is enough to cause the brakes to be applied with sufficient force to cause the predetermined rate of retardation of the vehicle for which the retardation controller is set, the pendulum 9 will be moved by inertia to the left sufficiently to cause engagement of the contact plate 56 with the contact members 51 to complete a circuit for energizing the magnet 5| of the magnet valve device I0, said circuit extending from the positive terminal of the battery 8| through the conductor 83, contact members 56 and 51, conductor 84, the coil of the magnet 5|, and the grounded conductor 85, to the grounded battery terminal 82.

Energization of the magnet 5| causes the stem 59 to be moved by the armature of the magnet 5|, so as to close the vent valve 4| and unseat the supply valve 38. Fluid under pressure is then supplied at a predetermined rate from the main reservoir 3 through the pipe I! and the restricted passage 40 to the valve chamber 39 of the magnet valve device, and thence past the unseated valve 38, and through the bore 45 and pipe 41 to the piston chamber 33 in the braking controller 8. The pressure of fluid in chamber 33 then gradually moves the piston 32 to the right, causing the rack 35 to rotate the pinion 36 and shaft 22 so as to turn the member 29 and the drum 2| toward the release position.

The member 29 in turning toward release position lessens the tension on the cable |5 so that the spring l4 of the self-lapping brake valve device is permitted to move the lever |2 in a counter-clockwise direction, thereby operating said brake valve device to effect a release of fluid under pressure from the brake cylinder 2. At the same time the turning of the drum 2| toward release position disengages the contact segment 21 successively from the contact fingers 88 so as gradually to connect resistance element 11 into the track brake circuit for reducing the supply of current to the track shoe 4. The above described automatic operation of the braking controller 8 is thus effective to release the brakes so as to reduce the rate of retardation of the vehicle.

The operator will, however, be aware of the control of the brakes by the retardation controller 10 When the rate of retardation of the vehicle is reduced by the above described partial release of the brakes sufficiently to permit the pendulum 53 of the retardation controller 9 to move out of engagement with the contacts 51, the magnet 15 of the magnet valve device will be deenergized,

allowing the spring 49 to seat the supply valve 38 and to unseat the vent valve 4|. Fluid under pressure will then be vented from the chamber 33 in the braking controller 8 by way of the pipe 20 41, bore 45, past the unseated valve 4| and through chamber 42 and passage 43 to the atmosphere. Further automatic movement of the braking corrtroller 8 is thus stopped, permitting the brakes to be freely controlled by the operator, who may,

25 if he so desires, again operate the handle 23 to effect another application of the brakes.

It will thus be seen that my invention provides means controlled by the retardation controller, in accordance with the rate of retardation of the 30 vehicle, operative to regulate the degree of application of the brakes by adjusting the position of the braking controller, thereby dispensing with the necessity for providing intermediate brake control mechanism that may be governed either 35 by the manually operable controller or by the retardation controller, depending upon which controller is effective to produce the lesser rate of retardation of the vehicle. In. addition to the structural simplification of the equipment em- 40 ployed, my invention permits the operator to retain control of the brakes as against the contrary influence of the retardation controller, when such control is deemed necessary.

While one illustrative embodiment of the in- 45 vention has been described in detail, it is not my intention to limit its scope to that embodiment or otherwise than by the terms of the appended claims.

Having now described my invention, what I 50 claim as new and desire to secure by Letters Patent, is:

1. In a vehicle braking system, in combination, an electrically controlled braking means, a brake Valve device for controlling a fluid pressure brake,

55 a manually movable braking controller operable to control said electrically controlled braking means, and operatively connected to said brake valve device to operate said brake valve device upon movement thereof, fluid pressure controlled 60 means for effecting the operation of said braking controller, and means controlled according to the rate of retardation of the vehicle for varying the fluid pressure on said fluid pressure controlled means.

65 2. In a brake equipment for vehicles, in combination, braking means, a manually operable brake controller for effecting the operation of said braking means to apply the brakes in accordance with the amount of movement thereof from its release position, a retardation controller responsive to the rate of deceleration of the vehicle, and means controlled thereby and effective upon a predetermined rate of retardation of the vehicle for actuating said manually operable brake controller to decrease the degree of application of said braking means.

3. In a brake equipment for vehicles, in combination, braking means, a brake controller for effecting the operation of said braking means to apply the brakes in accordance with the amount of movement thereof from its release position, biasing means for constantly urging said controller toward its release position, manual means for actuating said controller from its release position to efiect an application of the brakes, pneumatic means for biasing said controller toward its release position, and a retardation controller responsive to the rate of deceleration of the vehicle and operative upon a predetermined rate of retardation of the vehicle for rendering said pneumatic means effective.

4. In a brake equipment for vehicles, in combination, braking means, a brake controller for efiecting the operation of said braking means to apply the brakes in accordance with the amount of movement thereof from its release position, biasing means for constantly urging said controller toward its release position, manual means for actuating said controller from its release position to effect an application of the brakes, and

hicle and fluid pressure means controlled therei by for biasing said controller toward release position upon a predetermined rate of retardation of the vehicle.

5. In a brake equipment for vehicles, in combination, braking means, a braking controller operative to control the braking means, a retardation controller responsive to the rate of retardation of the vehicle, fluid pressure means controlled by said retardation controller for operating said braking controller, and manually operated means for actuating said braking controller and operable to resist operation of said braking controller by said fluid pressure means.

6. In a vehicle brake system, in combination, braking means, a braking controller adapted to effect the operation of said braking means to apply the brakes in accordance with the amount of movement thereof from its release position, fluid pressure controlled means adapted to bias said braking controller toward its release position, a retardation controller device operated according to the rate of retardation of the vehicle for varying the fluid pressure on said fluid pressure controlled means, and manually operated means operable to effect movement of said braking controller from its release position against the opposition of said fluid pressure controlled means.

CLYDE C. FARMER. 

